During the First World War, Horton had been one of Britain’s ablest submarine commanders. There could therefore have been no one better to lead the fight against the German U-boat menace as Commander-in-Chief Western Approaches from 1942. His overriding responsibility was for the safety of the convoys crossing the North Atlantic, a role that became increasingly important as the content of the convoys started to include US and Canadian troops coming to the UK for the invasion of Europe.
Horton joined the Royal Navy as an officer cadet at Dartmouth on 15 September 1898. By the outbreak of the First World War, he was already a lieutenant commander in command of one of the first British ocean-going submarines, the 800-ton HMS E9. Surface ships rather than other submarines were the more usual victims of submarine attack. On 13 September 1914, Lieutenant Commander Max Horton was in command of E9 when she surfaced 6 miles south of Heligoland to find the German light cruiser Hela only 2 miles away. Closing to a range of about 600 yards, E9 sent two torpedoes towards the enemy ship before diving. As the submarine dived, an explosion was heard. Surfacing, Horton found that his prey had stopped, but enemy gunfire forced him to dive again and to stay down for an hour. Surfacing again, he could see nothing other than trawlers searching for survivors. On his return to his base at Harwich, Horton flew the pirate flag, the ‘Jolly Roger’ skull and crossbones, establishing a tradition in the Royal Navy’s submarine service for boats returning from a successful operational cruise. Horton’s next success came on 6 October while patrolling off the Ems, when he torpedoed and sank the destroyer S-126.
In the face of growing German U-boat activity, it had been decided to take the offensive, sending British submarines to the Baltic, where they could in turn wreak havoc on German shipping, in effect giving the enemy a taste of his own medicine. The idea had first been floated at a conference with Jellicoe aboard the Iron Duke on 17 September 1914. By the time implementation was in hand, the proposed flotilla had become just three boats, E11, E9 and E1, with three hand-picked commanders, Lieutenant Commander Martin Nasmith, Lieutenant Commander Max Horton and Lieutenant Commander Noel Laurence respectively. Laurence was the senior officer.
Submarines were the only warships that could hope to enter the Baltic unobserved, at least in theory as the charts showed that there was not enough depth for submarines to submerge in the Kattegat, between Denmark and Sweden. Horton, commander of E9, suggested that the way to enter the Baltic was to run on the surface, but with the submarine trimmed down as low as possible in the water in the hope that at night the small conning tower of these early craft might not be noticed. His first patrol in the Baltic was nearly his last as he only narrowly missed being seen and rammed by a destroyer. German patrols were not the only hazard awaiting him. On one occasion his boat was frozen in port, and although he managed to get an ice-breaker to get out into the Gulf of Finland, once in the open sea E9 started to ice up, and frozen slush clogged vents and valves froze solid. Spray froze on the rigging wires, the torpedo-tube caps and the periscope. Horton was determined to discover whether or not E9 could still dive and to everyone’s surprise, once she submerged, the warmer water soon melted the ice and the submarine was able to operate normally. The other major problem was that the British submarines were using Russian ports, but as the Russian forces fell back before the German advance on the Eastern Front, they had to change bases constantly. Operations were finally abandoned in 1917 because of the Bolshevik Revolution.
Between the wars, Horton, now a captain, served as commanding officer of first HMS Conquest and of the battleship Resolution during the 1920s. He was promoted to rear admiral on 17 October 1932, flying his flag aboard the Queen Elizabeth-class battleship Malaya. Three years later he took command of the First Cruiser Squadron, flying his flag aboard London. Promoted to vice admiral in 1937, he commanded the Reserve Fleet.
At the outbreak of the Second World War, Horton was put in command of the Northern Patrol enforcing the distant maritime blockade of Germany in the seas between Orkney, Shetland and the Faeroes. In 1940, he was made commander of all home-based submarines, even though he was far more senior in rank than the C-in-C Submarines had traditionally been, due to a new Admiralty regulation that the C-in-C Submarines had to be an officer who had served aboard submarines in the First World War. Many believed that this regulation was forced through for the sole purpose of ensuring that Horton was on a very short list of qualifiers for the post, in order to ensure his rapid transfer to submarine headquarters at Aberdour, so great was the desire of some within the Admiralty to have him revitalize the submarine arm. Horton also had his own ideas and moved his headquarters from Aberdour, where he was subjected to the whims and prejudices of the fleet commanders at Scapa Flow, to Northways in north London. He claimed that this was because he wanted a freer hand in running his command, but many feel that it was because Northways was located near some of his favorite golf courses (he is said to have played a round of golf almost every day during the war).
He was promoted to the four-star rank of admiral on 9 January 1941 and was appointed Commander-in-Chief, Western Approaches Command on 17 November 1942. He took up his role as C-in-C Western Approaches at the most critical time of the war, with heavy losses to merchant shipping. Nevertheless, by May 1943, the situation had been transformed. He put in hand a series of changes in the way the escort ships were to be used. In addition to the escort group system, he oversaw the introduction of support groups, which would accompany the convoys but have the freedom to pursue submarines to destruction, being allowed to leave the convoy for long periods. These support groups proved to be decisive in the crucial spring of 1943, taking the battle to the U-boats and crushing the morale of the U-boat arm with persistent and successful counter-attacks.
Horton is widely regarded as one of the most crucial figures in the Allied victory in the Atlantic. The use of merchant aircraft carriers, the MAC-ships, and then escort carriers, helped close the Atlantic Gap – that section of the crossing that was beyond shore-based air cover – while the longer-range of aircraft such as the Consolidated Liberator also ensured greater security for the convoys. The increased number of purpose-built escort vessels, together with the Ultra intelligence that gave Horton the position of the U-boat wolf packs, all contributed to the Allied success. While much of this was the work of others, Horton was responsible for the overall control and coordination, and has been credited with showing untiring zeal, shrewdness and good strategic sense in the disposition of his forces. Perhaps his secret was that this successful submariner understood the workings of the minds of the U-boat commanders.
After the war, in August 1945, and at his own request, Max Horton was placed on the retired list in order to facilitate the promotion of younger officers. He was in any case past the peacetime retirement age. He was awarded the Knight Grand Cross in the Order of the Bath. He died on 30 July 1951 at the age of sixty-seven.